<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .zhu{
            display: flex;
            flex-direction: column;
            height: 300px;
            margin-bottom: 10px;
        }
        .zi{
            width: 100px;
            height: 100px;
            margin: 5px;
            background-color:aqua;
        }
    </style>
</head>
<body>
    <div class="zhu">
        <div class="zi">1</div>
        <div class="zi">2</div>
        <div class="zi">3</div>
    </div>
</body>
</html>